Suppression of temperature hysteresis in negative thermal expansion compound BiNi1-xFexO3 and zero-thermal expansion composite

Negative thermal expansion (NTE) of BiNi_1-xFe_xO₃ is investigated. All x = 0.05, 0.075, 0.10, and 0.15 samples shows large NTE with the coefficient of linear thermal expansion (CTE) α_L exceeding -150 ppm K^-1 induced by charge transfer between Bi⁵⁺ and Ni²⁺ in the controlled temperature range near room temperature. Compared with Bi_1-xLn_xNiO₃ (Ln: rare-earth elements), the thermal hysteresis that causes a problem for practical application is suppressed because random distribution of Fe in the Ni site changes the first order transition to second order-like transition. The CTE of BiNi_0.85Fe_0.15O₃ reaches -187 ppm K^-1 and it is demonstrated that 18 vol. % addition of the present compound compensates for the thermal expansion of epoxy resin.